1. Field of the Invention
The present invention is directed to an actively shielded, transversal gradient coil system for a nuclear magnetic resonance tomography apparatus, wherein saddle coils are provided in both primary and secondary planes for generating respective gradient fields for the X-direction and the Y-direction. These coils include a radial spacing, and the windings of the coils implemented in 3D technology include a plurality of open conductor ends wherein the contact between the conductor ends of the primary and secondary planes belonging to one another occurs via connector elements at an end face.
2. Description of the Prior Art
In contrast to the conventional, or through-wound, design of tesseral gradient coils, the 3D version includes a plurality of open conductor ends. Specific connector elements thereby produce the contact between a conductor loop of the primary plane with a winding of the secondary plane.
U.S. Letters Pat. No. 5,349,318, for example, discloses a gradient coil arrangement, wherein conductors of the gradient coil are essentially arranged in a primary plane, which is an inner cylindrical envelope, and in a secondary plane, which is an outer cylindrical envelope that concentrically surrounds the inner cylindrical envelope. At each of the two cylindrical envelopes, the conductor arrangement thereby contains a helical conductor section as well as a plurality of horseshoe-shaped conductor sections. At one end face of the cylindrical envelopes, the open conductor ends of the conductor sections between the two cylindrical envelopes are connected to one another via conductive connector wires. Pursuant to such configuration, the connector wires, for example, are soldered to the conductor ends.
With other gradient coils implemented in 3D technology, soldered pins are employed as connector elements which produce the connection between conductor ends that are formed as plates of sheet copper cut with a water jet. This type of connection, however, is actually more suitable for plane-parallel conductor structures. For curved surfaces, and given constricted space conditions, such pin connections hardly can be employed.
The present invention is therefore based on the object of creating a connection technology for the conductor loops of the primary and secondary planes that is simple and that can be applied for all conceivable applications of gradient coils in 3D technology.